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[RFC][Patch 2/4] kretprobe fast unregisteration
- From: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- To: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, "Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>, Prasanna S Panchamukhi <prasanna at in dot ibm dot com>
- Cc: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, linux-kernel <linux-kernel at vger dot kernel dot org>, SystemTAP <systemtap at sources dot redhat dot com>, Satoshi Oshima <soshima at redhat dot com>, Hideo Aoki <haoki at redhat dot com>, Yumiko Sugita <yumiko dot sugita dot yf at hitachi dot com>, "Frank Ch. Eigler" <fche at redhat dot com>
- Date: Fri, 23 Mar 2007 23:45:36 +0900
- Subject: [RFC][Patch 2/4] kretprobe fast unregisteration
- Organization: Systems Development Lab., Hitachi, Ltd., Japan
- References: <4603E7A4.50300@hitachi.com>
This patch introduces unregister_kretprobe_fast() for kretprobe.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
include/linux/kprobes.h | 12 +++++++++++-
kernel/kprobes.c | 44 ++++++++++++++++++++++++++++----------------
2 files changed, 39 insertions(+), 17 deletions(-)
Index: linux-2.6.21-rc4-mm1/include/linux/kprobes.h
===================================================================
--- linux-2.6.21-rc4-mm1.orig/include/linux/kprobes.h
+++ linux-2.6.21-rc4-mm1/include/linux/kprobes.h
@@ -202,7 +202,14 @@ void unregister_jprobe(struct jprobe *p)
void jprobe_return(void);
int register_kretprobe(struct kretprobe *rp);
-void unregister_kretprobe(struct kretprobe *rp);
+static inline void unregister_kretprobe(struct kretprobe *rp)
+{
+ unregister_kprobe(&rp->kp);
+}
+static inline void unregister_kretprobe_fast(struct kretprobe *rp)
+{
+ unregister_kprobe_fast(&rp->kp);
+}
struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
void add_rp_inst(struct kretprobe_instance *ri);
@@ -245,6 +252,9 @@ static inline int register_kretprobe(str
static inline void unregister_kretprobe(struct kretprobe *rp)
{
}
+static inline void unregister_kretprobe_fast(struct kretprobe *rp)
+{
+}
static inline void kprobe_flush_task(struct task_struct *tk)
{
}
Index: linux-2.6.21-rc4-mm1/kernel/kprobes.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/kernel/kprobes.c
+++ linux-2.6.21-rc4-mm1/kernel/kprobes.c
@@ -74,6 +74,8 @@ static struct notifier_block kprobe_page
.priority = 0x7fffffff /* we need to notified first */
};
+static int __kprobes is_kretprobe(struct kprobe *p);
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe->ainsn.insn points to the copy of the instruction to be
@@ -462,6 +464,20 @@ static inline void free_rp_inst(struct k
}
}
+static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
+{
+ unsigned long flags;
+ struct kretprobe_instance *ri;
+ /* No race here */
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ while ((ri = get_used_rp_inst(rp)) != NULL) {
+ ri->rp = NULL;
+ hlist_del(&ri->uflist);
+ }
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ free_rp_inst(rp);
+}
+
/*
* Keep all fields in the kprobe consistent
*/
@@ -697,6 +713,9 @@ static void __kprobes __unregister_kprob
if (atomic_add_return(-1, &kprobe_count) == \
ARCH_INACTIVE_KPROBE_COUNT)
unregister_page_fault_notifier(&kprobe_page_fault_nb);
+ if (is_kretprobe(p)) {
+ cleanup_rp_inst(container_of(p, struct kretprobe, kp));
+ }
return;
}
@@ -841,6 +860,11 @@ int __kprobes register_kretprobe(struct
return ret;
}
+static int __kprobes is_kretprobe(struct kprobe *p)
+{
+ return p->pre_handler == pre_handler_kretprobe;
+}
+
#else /* ARCH_SUPPORTS_KRETPROBES */
int __kprobes register_kretprobe(struct kretprobe *rp)
@@ -854,24 +878,13 @@ static int __kprobes pre_handler_kretpro
return 0;
}
-#endif /* ARCH_SUPPORTS_KRETPROBES */
-
-void __kprobes unregister_kretprobe(struct kretprobe *rp)
+static int __kprobes is_kretprobe(struct kprobe *p)
{
- unsigned long flags;
- struct kretprobe_instance *ri;
-
- unregister_kprobe(&rp->kp);
- /* No race here */
- spin_lock_irqsave(&kretprobe_lock, flags);
- while ((ri = get_used_rp_inst(rp)) != NULL) {
- ri->rp = NULL;
- hlist_del(&ri->uflist);
- }
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- free_rp_inst(rp);
+ return 0;
}
+#endif /* ARCH_SUPPORTS_KRETPROBES */
+
static int __init init_kprobes(void)
{
int i, err = 0;
@@ -1003,4 +1016,3 @@ EXPORT_SYMBOL_GPL(register_jprobe);
EXPORT_SYMBOL_GPL(unregister_jprobe);
EXPORT_SYMBOL_GPL(jprobe_return);
EXPORT_SYMBOL_GPL(register_kretprobe);
-EXPORT_SYMBOL_GPL(unregister_kretprobe);